Comment 3 for bug 1868626

ubuntu@eoan:~$ uname -r
5.3.0-46-generic
ubuntu@eoan:~$ grep -i lockdown /proc/cmdline
BOOT_IMAGE=/boot/vmlinuz-5.3.0-46-generic root=PARTUUID=486ca49b-7073-4f42-84a9-c3724b219786 ro console=tty1 console=ttyS0 lockdown
ubuntu@eoan:~$ dmesg | grep -i lockdown
[ 0.000000] Command line: BOOT_IMAGE=/boot/vmlinuz-5.3.0-46-generic root=PARTUUID=486ca49b-7073-4f42-84a9-c3724b219786 ro console=tty1 console=ttyS0 lockdown
[ 0.000000] Kernel is locked down from command line; see man kernel_lockdown.7
[ 0.019403] Kernel command line: BOOT_IMAGE=/boot/vmlinuz-5.3.0-46-generic root=PARTUUID=486ca49b-7073-4f42-84a9-c3724b219786 ro console=tty1 console=ttyS0 lockdown
[ 1.389113] Lockdown: swapper/0: Hibernation is restricted; see man kernel_lockdown.7
ubuntu@eoan:~$ sudo bpftrace -e 'tracepoint:syscalls:sys_enter_openat { printf("filename: [%s]; flags: [%d]\n", str(args->filename), args->flags); }'
Attaching 1 probe...
filename: [/proc/interrupts]; flags: [0]
filename: [/proc/stat]; flags: [0]
^C

ubuntu@eoan:~$ sudo bpftrace -e 'kprobe:do_nanosleep { printf("PID %d sleeping\n", pid); }'
Attaching 1 probe...
PID 509 sleeping
PID 509 sleeping
^C

ubuntu@eoan:~$